ZA site irratic, update process problems, etc.

Earlier today the ZA site would not recognize me, my password, etc. Tried to re-register but never got a reply. 6 hrs later all seems well. Glad I could wait.
Did an update but the process was sure tough. Options selected would disappear. Could not find options offered earlier. etc. Finally did a simple update. ZA lost money. Somebody needs to pay some attention to the site design.
Did pay for PC Tune-Up, but now cannot find it on the ZA site to download. The download button on the email receipt takes me to a page to start some sort of QA process but does not show a download option. If anyone can give me the address for this program it would be appreciated.
I decided to try this program because my PC has become so slow that sometimes I give up during the program loading process. Firefox takes forever to load these days.
Have WinXP(SP3) on a 5 yr old PC. The registry probably needs attention to solve the slowness issues so getting PC Tune-Up would be nice.